• Structural Engineering and Mechanics
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• 제63권5호
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• pp.639-646
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• 2017

According to the multi-index system of dam safety assessment and the standard of safety, a comprehensive evaluation model for dam safety based on a cloud model is established to determine the basic probability assignment of the Dempster-Shafer theory. The Dempster-Shafer theory is improved to solve the high conflict problems via fusion calculation. Compared with the traditional Dempster-Shafer theory, the application is more extensive and the result is more reasonable. The uncertainty model of dam safety multi-index comprehensive evaluation is applied according to the two theories above. The rationality and feasibility of the model are verified through application to the safety evaluation of a practical arch dam.

• ETRI Journal
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• 제38권1호
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• pp.90-99
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• 2016

In this work, we investigate differentially encoded blind transceiver design in low signal-to-noise ratio (SNR) regimes for orthogonal frequency-division multiplexing (OFDM) signaling. Owing to the fact that acquisition of channel state information is not viable for short coherence times or in low SNR regimes, we propose a time-spread frequency-encoded method under OFDM modulation. The repetition (spreading) of differentially encoded symbols allows us to achieve a target energy per bit to noise ratio and higher diversity. Based on the channel order, we optimize subcarrier assignment for spreading (along time) to achieve frequency diversity of an OFDM modulated signal. We present the performance of our proposed transceiver design and investigate the impact of Doppler frequency on the performance of the proposed differentially encoded transceiver design. To further improve reliability of the decoded data, we employ capacity-achieving low-density parity-check forward error correction encoding to the information bits.

• 통상정보연구
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• 제6권1호
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• pp.99-126
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• 2004

E-Trade is expected to dominate the global trade in the 21st century and thus is being introduced as a major policy assignment for each development country. e-trade has the potential to accelerate existing trends and introduce new ways of conducting trade. and e-trade is an alternative to strengthen international competitiveness. therefore, we needs to quickly adjust to this new method of e-trade and provide a number of policy suggestions that it can make best use of. However, successful implemetation, diffusion and usage of e-trade system require cooperation, commitment and the trust of all participating members in international trade process. A number of interorganizational, intraorganizational and innovation factors can influence both the extent to which e-trade is diffused and the level of subsequent performance that accure to participating firms. Considering the characteristics of e-trade, the proposed factors are based on an interdisciplinary study. The research model is based on the theories of innovation diffusion, inter-organizational system, and IS implementation. The factors proposed for this study of external firm factors, internal firm and perception factors.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.947-952
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• 2007

건설 프로젝트는 개별공종으로 구성되며 개별공종은 개별작업으로 이루어지므로 개별작업의 성과는 프로젝트 성과에 영향을 주는 최소단위이다. 그러므로 개별 작업에 대한 체계적인 성과측정 및 평가가 이루어져야 한다. 그러나 기존 성과측정은 기업 또는 프로젝트 단위에서 성과측정만 주로 이루어지고 있고 개별 작업을 측정하는 국내 ${\cdot}$ 외 공사관리체계에서는 지표에 대한 분석 및 활용이 미흡하다. 따라서 본 연구에서는 개별 작업을 측정하기 위해 PPC(Percent Plan Complete)를 성과지표로 선정하였고 통계적 분석 방법을 통해 목표지향적인 작업관리와 지속적인 개선이 이루어 질 수 있도록 지표의 분석 방법을 제안하였다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.531-534
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• 2007

현행 국내의 일괄입찰방식은 설계와 시공의 겸업금지로 공동도급 형태의 분담이행방식으로 운영되고 있어, 참여업체간의 의사소통 부족으로 인해 설계변경 클레임이 빈번하게 발생하고 있다. 또한 수행절차 과정에서도 사업참여자간 의견대립으로 인해 상호교류가 부족하여 프로젝트를 효율적으로 수행하는데 어려움이 있다. 이 연구에서는 일괄입찰방식, 파트너링과 시공성 분석의 특성을 파악하고, 예비적 고찰을 통한 상호교류의 영향도와 문제점을 분석하여, 일괄입찰방식 실시설계단계에서 프로젝트의 효과를 극대화 할 수 있는 효율적인 파트너링과 시공성 분석 연계 프로세스 모델을 제시하였다.

• Journal of Communications and Networks
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• 제15권1호
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• pp.102-110
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• 2013

This paper considers a cooperative orthogonal frequency division multiple access (OFDMA)-based cognitive radio network where the primary system leases some of its subchannels to the secondary system for a fraction of time in exchange for the secondary users (SUs) assisting the transmission of primary users (PUs) as relays. Our aim is to determine the cooperation strategies among the primary and secondary systems so as to maximize the sum-rate of SUs while maintaining quality-of-service (QoS) requirements of PUs. We formulate a joint optimization problem of PU transmission mode selection, SU (or relay) selection, subcarrier assignment, power control, and time allocation. By applying dual method, this mixed integer programming problem is decomposed into parallel per-subcarrier subproblems, with each determining the cooperation strategy between one PU and one SU. We show that, on each leased subcarrier, the optimal strategy is to let a SU exclusively act as a relay or transmit for itself. This result is fundamentally different from the conventional spectrum leasing in single-channel systems where a SU must transmit a fraction of time for itself if it helps the PU's transmission. We then propose a subgradient-based algorithm to find the asymptotically optimal solution to the primal problem in polynomial time. Simulation results demonstrate that the proposed algorithm can significantly enhance the network performance.

• Industrial Engineering and Management Systems
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• 제11권4호
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• pp.310-330
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• 2012

Scheduling is an important tool for a manufacturing system, where it can have a major impact on the productivity of a production process. In manufacturing systems, the purpose of scheduling is to minimize the production time and costs, by assigning a production facility when to make, with which staff, and on which equipment. Production scheduling aims to maximize the efficiency of the operation and reduce the costs. In order to find an optimal solution to manufacturing scheduling problems, it attempts to solve complex combinatorial optimization problems. Unfortunately, most of them fall into the class of NP-hard combinatorial problems. Genetic algorithm (GA) is one of the generic population-based metaheuristic optimization algorithms and the best one for finding a satisfactory solution in an acceptable time for the NP-hard scheduling problems. GA is the most popular type of evolutionary algorithm. In this survey paper, we address firstly multiobjective hybrid GA combined with adaptive fuzzy logic controller which gives fitness assignment mechanism and performance measures for solving multiple objective optimization problems, and four crucial issues in the manufacturing scheduling including a mathematical model, GA-based solution method and case study in flexible job-shop scheduling problem (fJSP), automatic guided vehicle (AGV) dispatching models in flexible manufacturing system (FMS) combined with priority-based GA, recent advanced planning and scheduling (APS) models and integrated systems for manufacturing.

• 정보처리학회논문지A
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• 제12A권2호
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• pp.145-150
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• 2005

최근 많은 프로세서 제작업체들이 프로세서의 효율을 높이기 위한 방법으로 독립적인 쓰레드들을 한 프로세서 사이클에 동시에 실행시킬 수 있는 동시다중 쓰레딩 기술을 구현하고 있으며 그 예의 하나가 하이퍼쓰레딩이다. 물리 프로세서 안에 여러 개의 논리 프로세서를 가질 수있는 하이퍼쓰레딩 기술은 기존의 여러 개의 독립적인 프로세서들을 갖춘 멀티 프로세싱 환경과는 차이가 있으며, 하이퍼쓰레딩 환경에 알맞은 특정한 작업 할당 방법이 필요하다. 따라서, 본 논문에서는 하이퍼쓰레딩 기술에 적합한 스케줄링 알고리즘을 제안하고 그 성능을 다양한 방법으로 측정해 봄으로서 하이퍼쓰레딩 시스템을 올바르게 인식하고 적절하게 관리하여 효율적인 성능을 기대할 수 있게 되었다.

• 한국정보처리학회논문지
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• 제4권7호
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• pp.1706-1718
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• 1997

다양한 소프트웨어 제품의 급격한 증가로 인하여 소프트웨어 제품의 평가·선정을 위한 체계적이고 객관적인 방법이 필요하게 되었다. 본 연구에서는 소프트웨어 제품의 효과적 평가·선정을 위해 평가 과정의 핵심인 가중치 부여와 모형의 선정에 중점을 둔다. 이를 위해 첫째, 계층적 분석 과정을 이용하여 평가 속성에 일관적 가중치를 부여한다. 둘째, 소프트웨어 제품의 선정 문제의 성격에 알맞은 모형을 조사${\cdot}$분류하여 모형별 장${\cdot}$단점을 분석한다. 적용 모형은 4개의 보상모형과 7개의 비보상모형으로 구성되어 있다. 선정된 모형은 특정 소프트웨어 제품(데이터베이스 모델러)에 응용되어 모형별로 제품을 평가한다. 본 연구는 가중치 부여 및 모형의 장·단점 분석과 응용 절차를 통하여 사용자의 다양한 요구사항에 대한 모형의 적용성을 제고하고자 한다.

• Journal of Biosystems Engineering
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• 제32권4호
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• pp.256-262
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• 2007

Image processing systems have been used to measure the plant parameters such as size, shape and structure of plants. There are yet some limited applications for evaluating plant colors due to illumination conditions. This study was focused to present adaptive methods to analyze plant leaf color regardless of illumination conditions. Color patches attached on the calibration bars were selected to represent leaf colors of lettuces and to test a possibility of health monitoring of lettuces. Repeatability of assigning leaf colors to color patches was investigated by two-tailed t-test for paired comparison. It resulted that there were no differences of assignment histogram between two images of one lettuce that were acquired at different light conditions. It supported that use of the calibration bars proposed for leaf color analysis provided color constancy, which was one of the most important issues in a video color analysis. A health discrimination equation was developed to classify lettuces into one of two classes, SOUND group and POOR group, using the machine vision. The classification accuracy of the developed health discrimination equation was 80.8%, compared to farmers' decision. This study could provide a feasible method to develop a standard color chart for evaluating leaf colors of plants and plant health monitoring system using the machine vision.